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Article Number: 100182
Software: RBACKUP Version ALL

This calculation considers only data transmission time in an optimally-configured system. Time for the Client software to prepare a backup by doing its compression and encryption is not a part of this calculation, and can be effected greatly by constraints outside the control of the software. Transmission speeds can vary widely from this calculation depending on outside factors like the configuration of the software, routers, firewalls, anti-virus software, ports, and CPU speeds. This calculation is for optimal connections. It is not intended for use as a benchmark or acceptance test for the software.

This calculation is based on the way RBackup Remote Backup software transmits and verifies files, NOT on any theoretically "perfect" file transmission formula. Our software adds overhead for authentication which is often very difficult to predict, as it is based on the current health and speed of the network connection between the Client and the Server, as well as the type of data and number of files in a backup set, and the speed of the processors in the Client and the Server.

Your transmission speed will vary. Use this only to estimate.

If your backups seem to be taking too long, please read this article: BACKUPS TAKE A REALLY LONG TIME.

This is an easy calculation. To do it you will need to know:

* The size of your data file(s) AFTER COMPRESSION, expressed in Bytes

* The speed of the slowest of the two internet connections - your Client or your Server, expressed in Baud

A typical data file set compresses to about 15% of its native size. Note: Some files compress more, and some do not compress at all. 15% is an average and may not be true in all cases.

When using this formula, express file sizes in BYTES.

1 Megabyte = 1,000,000 bytes
1 Gigabyte = 1,000,000,000 bytes

So, a 100 megabyte file set becomes 15 megabytes - 15,000,000 BYTES. One gigabyte becomes 150 megabytes - 150,000,000 BYTES. Use the COMPRESSED file size in the formula for calculating transmission time. To calculate compressed file size:

The table below lists some typical Internet connection speeds for various types of connections. Your Server will have an Internet connection, and so will your Client. Select the connection speed of the SLOWEST of the two.

Note: The table lists "typical" DOWNLINK speeds. Some Internet connections have much slower UPLINK speeds than DOWNLINK speeds. Your RBS Server uses mostly its DOWNLINK during RBS sessions (typically fast,) while your customers use mostly their UPLINKS (typically slow.)

Your Server will usually have a faster DOWNLINK speed than most of your customers' UPLINK speeds. There is no way to calculate exact UPLINK speed using this article. UPLINK speed is not a calculatable value. Internet Service Providers vary widely in the UPLINK speeds that they offer, usually from 25% to 100% of the DOWNLINK speed, with the higher UPLINK speeds costing significantly more for your customers.

When calculating total throughput from a Client to your Server, do the calculations using the slowest of the two speeds, which will usually be the customer's UPLINK speed. You might have to contact the customer to ask him what his UPLINK (or upstream, or "up") speed is.

The following table lists typical uplink and downlink speeds for common Internet connections. Cable and DSL UPLINK and DOWNLINK speeds vary widely among Internet Service Providers, between different geographical sections of the same network, with times of day, and with price and service plans. Cable and DSL speeds are usually higher during off-peak hours (at night) when fewer people are using the Internet, and when most Remote Backup sessions take place.

Now apply these numbers to the forumla for calculating file transmission times:

Let's assume you are sending 100 megabytes with a Cable Modem on the Client and a DSL on the Server, and that the UPLINK speed of the Cable Modem is 512K. First we'll reduce the 100 megabytes to 15 megabytes by compressing it, so 100 megabytes becomes 15 megabytes - 15,000,000 BYTES.

Sending one gigabyte over DSL:

(TECH)

(FAQ)

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